Carrier resin for pigment pastes, preparation and use thereof

Abstract

Carrier resin for pigment pastes, preparation and use thereof The invention relates to paste resins comprising (a) quaternary ammonium groups, (b) hydroxyl groups, (c) urethane radicals and (d) groups of the formula (I) ##STR1## in which R 1 to R 4 independently of one another represent hydrogen or a hydrocarbon radical of 1 to 10 carbon atoms and X denotes hydroxyl or a urethane radical, the average molecular weight (Mn) of these paste resins being 500 to 10,000. The invention further relates to the preparation of these paste resins, their use for pigment pastes as well as these pigment pastes. Water-thinnable paints, especially electrocoating paints which comprise the pigment pastes according to the invention, furnish, from a variety of substrates, surfaces free from defects and comparable film thicknesses.

What is claimed is: 
     
       1. Paste resins comprising (a) quaternary ammonium groups, (b) optionally hydroxyl groups, (c) optionally urethanes of the formula ##STR12## wherein R 5  is a hydrocarbon optionally interrupted with --O--, and (d) groups of the formula (I) ##STR13## in which R 1  to R 4  independently of one another represent hydrogen or a hydrocarbon radical of 1 to 10 carbon atoms, and X denotes hydroxyl or an urethane of the formula ##STR14## the average molecular weight (Mn) of these paste resins (Mn) of these paste resins being 500 to 10,000. 
     
     
       2. The paste resins as claimed in claim 1, wherein these paste resins contain on average 1 to 4 of the groups (a) and 1 to 6 of the groups (d) per molecule. 
     
     
       3. The paste resins as claimed in claim 1, wherein the number of the groups (b) is on average 1 to 20 per molecule. 
     
     
       4. The paste resins as claimed in claim 1, wherein the number of the groups (c) in the molecule is about 1 to 6 per molecule. 
     
     
       5. The paste resins as claimed in claim 1, wherein the urethane radicals (c) and X in the formula (I) are derived from monoisocyanates of 6 to 22 carbon atoms or from partly masked polyisocyanates of a total number of carbon atoms of 10 to 50. 
     
     
       6. The paste resins as claimed in claim 1, wherein the average molecular weight (Mn) is 1000 to 5000. 
     
     
       7. The paste resins as claimed in claim 1, which have hydroxyl values of 10 to 200 mg of KOH/g. 
     
     
       8. The paste resins as claimed in claim 1, wherein the amount of quaternary nitrogen is 0.2 to 20 milliequivalents per gram. 
     
     
       9. The paste resins as claimed in claim 1, which are self-curing. 
     
     
       10. A process for the preparation of the paste resins as claimed in claim 1, wherein polyamines (A) are first reacted with compounds (B) which contain at least one cyclic carbonate group and, optionally, hydroxyl groups, 1,2-epoxide groups and isocyanate groups, in such a manner that this reaction product (C) still contains quaternizable amino groups, and this reaction product (C) is then quaternized, optionally after a prior reaction with monoisocyanates of 6 to 22 carbon atoms or with partly masked polyisocyanates still having one free NCO group. 
     
     
       11. The process as claimed in claim 10, wherein at least one diamine from the group of diprimary diamines (A 2 ) and diamines (A 1 ) which contain a secondary or tertiary amino group in addition to a primary amino group, is used as the polyamine (A). 
     
     
       12. The process as claimed in claim 10, wherein as the compounds (B) compounds of the formula (IV) ##STR15## are used, in which denotes a z-valent radical of a polyether, polyether polyol, polyester, polyester polyol, which can also optionally contain (NR 13 ) groups, R 15  representing hydrogen, alkyl of 1 to 14 carbon atoms or hydroxyalkyl of 1 to 14 carbon atoms, or denotes a z-valent hydrocarbon radical, preferably an alkylene radical of 2 to 18 carbon atoms which can optionally also carry inert or non-interfering groups, or denotes a z-valent poly(sec.)amine radical or denotes the z-valent radical of a reaction product of an epoxide-carbonate compound with polyamines, polyols, polycaprolactone polyols, hydroxyl group-containing polyesters, polyethers, polyglycols, hydroxyl function-containing, carboxyl function-containing and amino function-containing polymeric oils having average molecular weights of 800 to 10,000, polycarboxylic acids, hydroxyl function-containing or amino function-containing polytetrahydrofurans and reaction products of polyamines with glycidyl esters of α,α-dialkylalkanemonocarboxylic acids of the empirical formula C 12-14  H 22-26  O 3  or with glycidyl versatate, denotes 1 to 5. 
     
     
       13. The process as claimed in claim 10, wherein (A 1 ), (A 2 ) and (B) are used in amounts of 28 to 80 mole %, 0 to 40 mole % and 20 to 60 mole %. 
     
     
       14. The process as claimed in claim 10, wherein the quaternization is carried out by a reaction of (C) with a monoepoxide in an acid medium. 
     
     
       15. Pigment pastes comprising the paste resins according to at least claim 1 and a pigment dispersed therein.